The reason why cylindrical tanks for LPG (liquid propane gas) fuel systems for vehicles are so widespread is that, for many years now they have been the only type of fuel tank of this kind available. These cylindrical tanks feature the valve group ring located right in the middle of the tank or on the side of the cylindrical ferrule. The tank is generally located in the trunk against the rear seat back or in the space between the two rear wheels. The fact that the valve group and, even worse, the airtight chamber, are placed right in the middle creates an additional impediment, besides the tank itself, with the obvious reduction of the trunk's loading capacity and seeing that the airtight chamber often has projecting parts of its own this also entails the risk of damaging any luggage or packages one puts inside the trunk. Furthermore, in order to access the valve group, in case of need, it is necessary to empty the trunk of all its contents, given the position of the valve group right in the middle of the tank.